Lock-down mechanism

ABSTRACT

A lock-down mechanism for a floating platform for use in doff trucks and the like. The lock-down mechanism is carried adjacent the upper ends of a pair of lazy tongs so that its operation is not effected by lint and other foreign matter accumulated in the bottom of the doff truck. The lock-down mechanism includes a pivotal arm that is spring biased in an initial position. As the floating platform is lowered the pivotal arm is moved towards a keeper and engages an inclined notch therein. By lowering the floating platform further the pivotal arm passes around the keeper to its initial position allowing the platform to be raised.

United States Patent [15] 3,659,913 Waldron et al. 1 May 2, 1972 [54] LOCK-DOWN MECHANISM 3,418,031 12/1968 Fisher ..3|2/71 x [72] Inventors: Linwood J. Waldron, Dover; William J.

Hastings Rochester both of NH Primary Exan merJames C. Mitchell AnorneyBa1ley & Dority [73] Assignee: Spaulding Fibre Company, Inc., North Rochester, NH. [57] ABSTRACT Filedi 1970 A lock-down mechanism for a floating platform for use in doff [21] Appl No: 62 103 trucks and the like. The lock-down mechanism is carried adjacent the upper ends of a pair of lazy tongs so that its operation is not effected by lint and other foreign matter accumu- [52] US. Cl ..312/71, 220/93 [med in the bottom of [he doff truck The lock down [51] 111(- CI. i ..A-47f 1/00 mechanism includes a pivotal arm that is Spring biased in an Fleld of Search 1 1 312, initial position. AS the fl fi g platfonn is lowered he pivotal Ci d arm is moved towards a keeper and engages an inclined notch [56] Re erences te therein. By lowering the floating platform further the pivotal UNITED STATES PATENTS arm passes around the keeper to its initial position allowing the platform to be raised. 2,980,287 4/1961 Fisher ..220/93 3,091,503 5/1963 Fisher ..312/71 4 Claims, 7 Drawing Figures I O 2 I 3 17 26 i6 4 15 i A 3 ;%-ee'::;=" :'".t"?"" 2 2 g D 24 5 D B Q\ C 5 2i Patented May 2; 1972 3,659,913

2 Sheets-Sheet 1 IO o 10 War i m I H D\; D

INVENTORS.

LINWOOD d. WALDRON BY {'LWILLIAM J. HASTINGS ATTORNEY;

Patented May 2, 1972 3,659,913

2 Sheets-Sheet 2 INVENTORS. F LINWOOD d. WALDRON H fiWlLLlAM \J. HAsTmes 29- 7 6 m A TTORNE 5 LOCK-DOWN MECHANISM This invention relates to a lock-down mechanism for a floating platform which is used in doff trucks and the like, and more particularly to a lock-down mechanism which is carried adjacent the floating platform in the top of the doff truck so that foreign matter does not interfere with its operation.

Lock-down mechanisms for floating platforms carried in doff trucks, spool troughs, etc. are well known, and examples are illustrated in U.S. Pat. Nos. 3,418,031, 2,980,287, and 3,091,503, granted to J. C. Fisher. One of the problems with lock-down mechanisms heretofore used is that they are carried in the bottom of the doff trucks and frequently the operation of such is interfered with by accumulations of lint and other foreign matter.

Accordingly, it is an important object of the present invention to provide a lock-down mechanism for a floating platform which is carried adjacent the platform so that foreign matter in the bottom of the receptacle in which the platform is used does not interfere with the operation thereof.

Another important object of the present invention is to pro vide a lock-down mechanism for a floating platform which includes a pivotal arm that is pivoted in a horizontal plane to a locking position in a keeper and by lowering the platform further is pivoted in the horizontal plane around the keeper to release the platform.

Another important object of the present invention is to provide a lock-down mechanism for a floating platform which is simple to construct and relatively fool proof in its operation.

The construction designed to carry out the invention will be hereinafter described, together with other features thereof.

The invention will be more readily understood from a reading of the following specification, and by reference to the accompanying drawings forming a part thereof wherein, an example of the invention is shown and wherein:

FIG. I is a side elevational view of a doffing truck, partially in section, illustrating a floating platform with a lock-down mechanism mounted thereon constructed in accordance with the present invention,

FIG. 2 is a side elevational view, partially in section, illustrating the floating platform in a depressed lock-down position,

FIG. 3 is a sectional view taken along line 33 of FIG. 1,

FIG. 4 is a plan view, with parts removed, illustrating the lock-down mechanism in the unlocked position as is the case when the floating platform is in the raised position,

FIG. 5 is a fragmentary plan view, illustrating the lock-down mechanism in the locked position as when the floating platform is in the depressed position, such as illustrated in FIG. 2,

FIG. 6 is a fragmentary plan view showing the pivotal arm of the latching member (dotted lines) moving around the keeper to the released position, and

FIG. 7 is a transverse sectional view taken along line 7-7 of FIG. 4.

Referring to the drawings, there is illustrated a lock-down mechanism for a floating platform A, which is supported on a pair of opposed lazy tongs B, each formed of a pair of cross bars pivotally connected together. The lazy tongs are, in turn, supported on a base supporting member C. One of the cross bars of each pair has an upper end connected to the floating platform A. Means is provided for slidably connecting an upper end of the other cross bar of each of the pairs to the floating platform A. Means is provided for slidably connecting a lower end of said one cross bar of each of the pairs to the base supporting member. The other of said cross bars of each pair has a lower end connected to the base supporting member C. Spring means D are carried on the base supporting member forcing the floating platform A upwardly. The lock-down mechanism includes a keeper E. and a pivotal latching member F. Means are provided for supporting the latching member and the keeper adjacent an upper end of the lazy tongs for movement relative to each other in a horizontal plane responsive to the platform A being lowered. The latching member F includes a pivotal arm. An upwardly extending post is carried adjacent one end of the pivotal arm. The keeper E has a leading edge inclined away from the latching member F, a trailing edge spaced a predetermined distance from the leading edge, and a horizontal planar side portion joining the leading and trailing edge. A notch G is interposed in the side portion inclined towards the trailing edge. Spring means H is attached to the other end of the pivotal arm F urging the pivotal arm in a first position so that as the platform is lowered the post rides around the leading edge of the keeper E into the notch G in the side portion locking the platform in a depressed position. As the platform is lowered further, the post moves out of the notch G around the trailing edge allowing the platform to be raised. Thus, the lock-down mechanism is carried adjacent the floating platform and its operation is not effected by foreign matter collecting adjacent the base member.

The floating platform A may be used in many different applications, and the particular one illustrated in the drawings is in a conventional doff truck. The doff truck includes a pair of vertical side walls 10 and II which are joined by vertical end walls I2 and 13, respectively. The walls are joined by a bottom 14. Casters 15 are carried on the bottom for transporting the doff truck. The floating platform has a flat elongated supporting board 16 carried thereon for supporting spools, bobbins and the like within the truck. This platform 16 is only illustrated in FIGS. 1 and 2 and is removed so as to show the working mechanism in FIGS. 3 through 7. The platform 16 is substantially the same dimension as the opening in the doff truck and fits closely adjacent the walls 10 through I3.

The floating platform A is constructed of a pair of elongated spaced angle-irons 17 and 17a, respectively, which are joined by angle-irons l8 and 19, respectively, to define a rectangular shaped frame. The side angle-irons 17 and 17a have flat cross braces 20 welded on the top thereof, upon which the flat supporting board 16 rests. The base supporting member C is identical to the floating platform A and is also constructed of angle-irons and, as a result, the same reference characters will be used for similar parts. The base supporting member is turned upside down from the floating platform and, as a result, the cross braces 20 rests on the bottom 14 of the doff trucks. Additional angle-irons 21 are attached to the end angle-irons l8 and I9, respectively, of the base supporting member so that the base supporting member fits snuggly within the doff truck and is not allowed to shift in the horizontal direction. It will be noted that the horizontal faces of the angle-irons 21 rest on the bottom 14 of the doff truck and terminate adjacent the end walls 12 and 13.

The floating platform A is supported on a pair of lazy tongs B. Each of which is formed by a pair of cross bars 22 and 23, respectively, which are pivotally connected in a medial portion thereof by a pin 24 extending therethrough. The upper end of one of the cross bars 23 of each pair is pivotally connected to the side angle-irons I7 and 170, respectively, by a pin 25 extending therethrough. The upper end of the other cross bar 22 is slidably connected in an elongated slot 26 in the angle-irons l7 and 17a. The operation and construction of only one lazy tong will be described and it is to be understood that the lazy tong carried on the other side of the floating platform cooperates therewith, and it is identical thereto. An elongated channel shaped member 27 is slidably carried adjacent the inner surface of the vertical flange of each of the angleirons l7 and 17a. A pin 28 passes through a hole in the channel shaped member 27, the elongated slot 26 and a hole in the upper end of the cross bar 22. An enlarged head is carried on the inner end of the pin, while a cotter pin 29 extends through the outer end. This connection allows the channel shaped member 27 to slide relative to the side frames I7 and as the upper end of the cross bars 22 shift relative to the side angle-irons I7 and 17a when the floating platform is raised and lowered. An elongated angle-iron 30 is welded to the inner edge of each of the angle-irons l7 and 17a and has a horizontal portion which extends inwardly towards the channel shaped member 27 so that the upper flange 31 of the channel shaped member 27 rests on the inwardly inturned flange of the angle-member 30 as the channel member 27 is shifted in the horizontal direction. When the pin 28 strikes the inner end of the elongated slot 26 such limits the upward movement of the floating platform A. The outer end of the elongated slot 26 limits the distance that the floating platfonn can be lowered.

Coil springs D are interposed between the base supporting member C and the floating platform A for urging the floating platform upwardly. As the load on the supporting board 16 increases the springs D are compressed accordingly.

A cross brace 32 extends between the opposed channel shaped members 27 and is welded to the bottom flange thereof so as to move therewith. This cross brace 32 is provided for supporting the pivotal latching member F. The keeper E is supported on another cross brace 33 which is welded to the horizontal flange portion of the side angle-irons l7 and 170, respectively. Thus, the brace 33 is fixed relative to the floating platform 17a, while the brace 32 is allowed to shift longitudinally, as indicated by the arrow in FIG. 6, when the floating platform is raised and lowered.

The keeper E is constructed of angle-iron with a vertical flange portion 34 being welded to the bottom side of the cross brace 33. A horizontal flange portion 35 is spaced vertically from the cross brace 33 a distance of approximately 1 inches, depending on the size of angle-irons being used. The horizontal flange portion 35 has a leading edge 36 inclined away from the latching member and a trailing edge 37 spaced a predetermined distance from he leading the It is noted that the horizontal flange 35 has a side portion which is also inclined at approximately 30 from a horizontal axis as viewed in FIG. 6. A notch G is interposed in the side portion of the horizontal flange member 35, and is also inclined rearwardly towards the trailing edge 37.

A V-shaped abutting angle member 38 is welded to the bottom side of the cross brace 33 a distance sufficient to allow an upwardly extending post 39 carried on the end of the pivotal latching member F, to pass between the keeper E and the abutting member 38.

The pivotal latching member F includes a pivotal arm 40 which is constructed of a flat elongated piece of metal. The pivotal arm 40 is pivotally connected to the cross brace 32 by a pin 41 which has enlarged ends to secure the pivotal arm to the cross brace 32. The upwardly extending post 39 is carried adjacent one end of the pivotal arm 40. The spring means H is provided for urging the pivotal arm 40 to an initial position parallel to the side angle-irons 17 and 170. This spring means H includes a laterally extending brace 42 which has one end welded to the cross brace 32. An elongated spring 43 has one end connected through a hole carried in the other end of the brace 42. The other end of the spring 43 is coupled to the pivotal arm 40 through a hole extending in the opposite end of the pivotal arm from that upon which the post 39 is located. The laterally extending brace 42 is located in the center of the cross brace 32, while the notch G in the keeper is positioned slightly towards the side brace 17 therefrom. The reason for this will become apparent from the description of the operatron.

In operation, when the floating platform A is in the raised position, such as illustrated in FIG. 1, the pivotal latching member F is in the position illustrated in FIG. 4. As the pressure on the floating platform increases the springs D and the lazy tongs B are depressed. This causes the channel shaped member 27 and the cross brace 32 to move to the right. When the platform reaches the position illustrated in FIG. 2 the cross brace 32 is in the position shown in FIG. 5. Immediately prior to latching, the post 39 engaged the inclined leading edge 36 of the keeper riding over such into the inclined notch G, as illustrated in FIG. 5. In order to release the lock-down platform from the position illustrated in FIG. it is merely depressed further causing the post 39 to move out of the inclined notch G around the trailing edge 37 of the keeper through the passageway between the abutment 38 and the trailing edge 39. The spring 43 causes the pivotal arm 40 to return to the parallel position, as illustrated in FIG. 6, releasing the floating platform A. The springs D then return the floating platform A to the position, as illustrated in FIG. 1, when the weight is removed therefrom.

Thus, it can be seen that since the latching mechanism is carried adjacent the top of the floating platform the operation of such is not interfered with by lint and the like carried in the bottom of the doff truck.

While a preferred embodiment of the invention has been described using specific terms, such description is for illustrative purposes only, and it is to be understood that changes and variations may be made without departing from the spirit or scope of the following claims.

What is claimed is:

l. A lock-down mechanism for a floating platform, including a pair of opposed lazy tongs each formed of a pair of cross bars pivotally connected together, a base supporting member, one of said cross bars of each pair having an upper end connected to said floating platform, means for slidably connecting an upper end of the other cross bar of each of said pairs to said floating platform, means for slidably connecting a lower end of said one cross bar of each of said pairs to said base supporting member, said other of said cross bars of each pair having a lower end connected to said base supporting member, spring means carried on said base supporting member forcing said platform upwardly, the improvement comprising; a lock-down mechanism, including a keeper and a pivotal latching member, means for supporting said latching member and said keeper adjacent an upper end of said lazy tongs for movement relative to each other in a horizontal plane responsive to said platform being lowered, said latching member including a pivotal am, an upwardly extending post carried adjacent one end of said pivotal arm, said keeper having a leading edge inclined away from said latching member, a trailing edge spaced a predetermined distance from said leading edge, and a horizontal planar side portion joining said leading and trailing edge, a notch interposed in said side portion inclined toward said trailing edge, and spring means attached to the other end of said pivotal arm urging said pivotal arm in a first position so that as said platform is lowered said post rides around said leading edge of said keeper into said notch in said side portion locking said platform in a depressed position, and as said platform is lowered further said post moves out said notch around said trailing edge allowing said platform to be raised, whereby said lock-down mechanism is carried adjacent the floating platform and its operation is not effected by foreign matter collecting adjacent said base supporting member.

2. The lock-down mechanism as set forth in claim 1, wherein said keeper is fixed to said floating platform and means for coupling said latching member to the upper end of said other cross bar for movement therewith towards said keeper as said floating platform is lowered.

3. The lock-down mechanism as set forth in claim 1. wherein a cross brace is carried between said upper ends of said other cross bars and moves with said upper ends of said other cross bars in a horizontal direction as said platform is lowered, a laterally extending brace carried by said cross brace, said pivotal arm being pivotally supported on said cross brace and said spring means attached to one end of said pivotal arm is a spring having one end attached to said one end of said pivotal arm, and the other end attached to said laterally extending brace.

4. A lock-down mechanism for a floating platform, including a pair of opposed lazy tongs each fonned of a pair of cross bars pivotally connected together, a base supporting member, one of said cross bars of each pair having an upper end connected to said floating platform, means for slidably connecting an upper end of the other cross bar of each of said pairs to said floating platform, means for slidably connecting a lower end of said one cross bar of each of said pairs to said base supporting member, said other of said cross bars of each pair having a lower end connected to said base supporting member, spring means carried on said base supporting member forcing said platform upwardly, the improvement comprising; a lock-down mechanism, including a keeper and a pivotal latching portion joining said leading and trailing edge, a notch interposed in said side portion inclined toward said trailing edge, and spring means attached to the other end of said pivotal arm urging said pivotal arm in a first position so that as said platform is lowered said post rides around said leading edge of said keeper into said notch in said side portion locking said platform in a depressed position, and as said platform is lowered further said post moves out said notch around said trailing edge allowing said platform to be raised.

# I I! t t 

1. A lock-down mechanism for a floating platform, including a pair of opposed lazy tongs each formed of a pair of cross bars pivotally connected together, a base supporting member, one of said cross bars of each pair having an upper end connected to said floating platform, means for slidably connecting an upper end of the other cross bar of each of said pairs to said floating platform, means for slidably connecting a lower end of said one cross bar of each of said pairs to said base supporting member, said other of said cross bars of each pair having a lower end connected to said base supporting member, spring means carried on said base supporting member forcing said platform upwardly, the improvement comprising; a lock-down mechanism, including a keeper and a pivotal latching member, means for supporting said latching member and said keeper adjacent an upper end of said lazy tongs for movement relative to each other in a horizontal plane responsive to said platform being lowered, said latching member including a pivotal arm, an upwardly extending post carried adjacent one end of said pivotal arm, said keeper having A leading edge inclined away from said latching member, a trailing edge spaced a predetermined distance from said leading edge, and a horizontal planar side portion joining said leading and trailing edge, a notch interposed in said side portion inclined toward said trailing edge, and spring means attached to the other end of said pivotal arm urging said pivotal arm in a first position so that as said platform is lowered said post rides around said leading edge of said keeper into said notch in said side portion locking said platform in a depressed position, and as said platform is lowered further said post moves out said notch around said trailing edge allowing said platform to be raised, whereby said lock-down mechanism is carried adjacent the floating platform and its operation is not effected by foreign matter collecting adjacent said base supporting member.
 2. The lock-down mechanism as set forth in claim 1, wherein said keeper is fixed to said floating platform and means for coupling said latching member to the upper end of said other cross bar for movement therewith towards said keeper as said floating platform is lowered.
 3. The lock-down mechanism as set forth in claim 1, wherein a cross brace is carried between said upper ends of said other cross bars and moves with said upper ends of said other cross bars in a horizontal direction as said platform is lowered, a laterally extending brace carried by said cross brace, said pivotal arm being pivotally supported on said cross brace and said spring means attached to one end of said pivotal arm is a spring having one end attached to said one end of said pivotal arm, and the other end attached to said laterally extending brace.
 4. A lock-down mechanism for a floating platform, including a pair of opposed lazy tongs each formed of a pair of cross bars pivotally connected together, a base supporting member, one of said cross bars of each pair having an upper end connected to said floating platform, means for slidably connecting an upper end of the other cross bar of each of said pairs to said floating platform, means for slidably connecting a lower end of said one cross bar of each of said pairs to said base supporting member, said other of said cross bars of each pair having a lower end connected to said base supporting member, spring means carried on said base supporting member forcing said platform upwardly, the improvement comprising; a lock-down mechanism, including a keeper and a pivotal latching member, means for supporting said latching member and said keeper adjacent one end of said lazy tongs for movement relative to each other in a horizontal plane responsive to said platform being lowered, said latching member including an elongated pivotal arm, means for supporting said elongated pivotal arm for pivotal movement in a horizontal plane, an upwardly extending post carried adjacent one end of said pivotal arm, said keeper having a leading edge inclined away from said latching member, a trailing edge spaced a predetermined distance from said leading edge, and a horizontal planar side portion joining said leading and trailing edge, a notch interposed in said side portion inclined toward said trailing edge, and spring means attached to the other end of said pivotal arm urging said pivotal arm in a first position so that as said platform is lowered said post rides around said leading edge of said keeper into said notch in said side portion locking said platform in a depressed position, and as said platform is lowered further said post moves out said notch around said trailing edge allowing said platform to be raised. 